Tire signal and system



Juy S, 15ML R. ADDY ET AL TIRE SIGNAL AND SYSTEM Filed O01. l2, 1939 WVENTORS l l D0 s zum" llrlllil l vPatented July 8, 1941 UNITED STATES PATENT oFFlcE TIRE SIGNAL AND SYSTEM Roy Addy and Henry E. Addy, Milwaukee, Wis.

Application October 12, 1939, Serial No. 299,053 t (c1. coi-4s) s cum This invention relates to improvements in re spect to automatically operating pressure signaling systems for the pneumatic tires on automobiles and other motor vehicles.

The principal purpose and object of our invention is to provide a tire signaling system which is not only simple in construction and operation, but which may be readily and easily applied to automobiles or other vehicles already in use or as standard equipment.

Avfurther object of our invention is to provid a signaling system in which the pressure responsive devices are in unit form and are mountable on the wheel structures of the respective wheels .of the vehicle. A

A further object of our invention is to provide pressure responsive devices which are not only compact and simple in construction, but are of a size adapting them to fit within the space between the wheel body and its removable hub cup.

A further object of our invention is to have the pressure responsive element of each unit in the form of a diaphragm of resilient material such as rubber and which diaphragm is constructed to have alined tubular portions on opposite sides of a radial portion which enables the diaphragm to be clamped in place between the base and the outer casing members which mount and house the diaphragm. The further object of our invention is to provide in connection with the diaphragm a spring biased plunger, the acting pressure of which may be readily and easily adjusted to the selected operative pressure for the vehicle tire.

A further object of our invention is to provide the system with a set of electric lamps, one for each wheel',4 and a gauge common to all of the lamps for indicating the pressure condition within the tires whenever the gauge is connected into the electric circuit with a lamp.

A further object of our invention is to associate the switch means for the gauge with the lamps and have each lamp slidably mounted so that the switch for the gauge may be actuated by pressing inward on the selected lamp.

'I'he invention consists further in the features hereinafter described and claimed.

In the accompanying drawlng- Fig. l is a diagrammatic view'illustrating the application of our invention to a motor vehicle;

Fig. 2 shows a pressure responsive device of our invention in its application to one of the wheels of the vehicle, the view being broken away and in section respectively;

Fig. 3 shows said pressure responsive device in longitudinal section; and

Fig. 4 is a wiring diagram to be hereinafter described.

As shown in Fig. `3,- the pressure responsive device of our invention comprises a cylindrical outer casing I and a base member 2. These elements are secured together in longitudinal alinement, there being a screw threaded connection between them at their meeting ends as shown. The member 2 is provided with a pressure chamber 3 and a pair ot passages l. l extending through the member 2 and connected into the` chamber` adjacent the bottom thereof. One passage, for example, the passage l, is connected with the infiating stem of the associated pneumatic tire. In Fig. 2, the stem is indicated lat 0 and the rubber or other flexible tube which connects the passage I with said siem is marked 1.

'I'he other passage l extends through a boss l on the member 2 and said boss provides a mounting for an inflating valve fixture 9 through which the associated tire may be inflated in the usual manner. The member 2 is also provided with a boss III for the passage l and said boss is screw threaded so that the conduit I may be connected thereto as shown.

From the foregoing, it is apparent, that the inner tube of the tire with which the device I-2 is associated is innated through the chamber l in the member 2 and hence the pressure in said chamber is the same as within the inner tube of the tire. The inner tube is shown at II in Fig. 2, while the tire casing is marked I2.

The outer casing I is provided with a chamber I3 which registers with the chamber 2 when the parts are assembled as shown in Fig. 3. The chamber I2 is formed by a tubular protection Il on the bottom wall Il of the casing I. The chambers 3 and I 3 are preferably of the same diameter so that the two provide in etlect a continuous chamber, one portion of which is within the member 2 and the other portion is within the casing I. Located within this combined chamber is a flexible rubber diaphragm I8 having oppositely extending tubular portions I1, Il of approximately the same diameter. The portions I'I, I8 flt within their respective chambers 3 and I3 and engage against the cylindric walls thereof. The portions I1 and I 8 are integrally connected in respect to each other and also in respect to an exterior radial flange section Il by means of which lthe portions Il, Il are held in place within the chambers l and Il. The ilange I9 is annular and is clamped between the casing I and the member 2 when such parts are secured together. The member 2 has a dat surface 24 to seat the flange i3 of the diaphragm.

The tubular portions I1 and I 3 open into the chamber 3 and hence the air pressure in said chamber nnds entry into the tubular portions to press them against the chamber walls on opposite sides of the flange It. This has the dual purpose of preventing air leakage out of the chambers 3 and I3 at the flange I3 and to support the end thrust of a plunger (to be presently referred to) on the tubular portion i8 at its end wall 2|. 'I'he latter is integral with the outer end of the tubular portion I3 and provides a closure therefor as shown.

The plunger referred to is located within the outer casing and extends through an opening in the end wall 22 of the projection I4 to reach the rubber element I6. The plunger is marked 23 and is spring biased against the end wall 2| of said rubber member in opposition to the air pressure within the chamber 3. As this air pressure reduces, the plunger 23 moves the wall member 2| further inward by reason of the flexible nature of the member I6. As the wall section 2| moves into the tubular portion Il, the rubber structure doubles on itself as shown in Fig. 3.

The spring which moves the plunger inward is marked 24 and is housed within the plunger, the latter being made hollow as shown. The inner end of the spring 24 seats against the bottom wall of the plunger, that is, the plunger wall which rests on the diaphragm wall 2|, while the outer end of the spring bears against a nut 2l on a screw threaded rod 23. Said rod extends axially oi' the plunger and has its outer end projecting through a closure plate 21 at the outer end of the caslng This plate may have a screw threaded connection with the casing as shown.

'I'he outer end of the rod 2i may be slotted or otherwise formed to receive a tool for turning the rod to adjust the tension of the spring 24 through the nut 25. The rod is provided with a rigid collar 23 which is pressed by the spring against the inner side of the plate 21 to hold the rod in place. The nut 25 is prevented from turning by having a pin 29 on the nut extending into an axially extending slot 34 in the plunger 23. The latter has a similar connection with the outer casing I to hold the plunger from rotatiOn.

The plunger 23 carries a spool element 3| within the outer casing I. Said spool is of electrical insulation material and provides a mounting for a coil of electrical resistance wire 32. This coil is about the outer periphery ofthe spool and is engaged by a spring contact nger 33 xed within the outer casing by a terminal 34 as shown in Fig. 3. The linger 33 slides over the coil in the endwise movement of the plunger and controls the amount of current flow through the coil to indicate at a gauge 35 the pressure condition within the associated vehicle tire. The coil 32 is grounded through the plunger 23 by a lead 35.

The plunger 23 is provided at its outer end with a disc-like element 31 having a peripheral projection 38 riding in an axially extending slot 33 in the outer casing I. This holds the plunger against turning, the disc 31 having a rigid connection with the plunger. The disc 31 carries an axially extending rod-like element 4l located in the space between the coil 32 and the adjacent outer wall of the casing 'I'he element 4l is provided with a stop, 4| at its inner end to contact with a terminal 42 fixed to the outer casing and in an electrial circuit with a lamp and a sounder, respectively. The purpose of this stop is to sound an alarm when the tire is over innated. When the plate 31 contacts the terminal 42, the alarm is sounded to indicate an under inflation. The spool 3| is cored `oui; at its inner end as indicated at 43 to accommodate the projection I4 when the plunger moves towards the projection. This contributes to the compactness of the device in an axial direction.

The pressure responsive device |-2 is mounted on the wheel of the vehicle beneath the hub cap 44 as shown in Fig. 2. This encloses the device within the wheel structure and protects it. The device is mounted on the hub section 4i of the wheel structure 48 by a bracket 41. The latter is preferably carried by the closure plate 21 oi the device and is secured to the hub section of the wheel structure by one or more bolts or screws 4l. 'I'he pressure responsive device is preferably mounted in place with its inilating valve fixture 3 readily accessible on taking of! the hub cap. In keeping with this object, the device |-2 is located on the outer side of the wheel structure 44 as shown herein.

A pair of conductor rings 49, 50 are located within the brake drum housing 5I of the wheel. said rings being secured to an insulation annulus 52 rotating with the wheel on its axle part i3. The latter is on the front or outer side oi' the brake drum assembly and mounts the brake drum casing Il as shown. The axle is marked I4. -The rear cover plate 55 of the brake drum assembly carries a pair oi brushes 56, 51 which press against the respective conductor rings 4I, 5B. These brushes have resilient contact with the rings and are carried by an insulation block il secured to the brake drum cover. The latter is non-rotative, being secured to the adjacent stationary flange 53 of the axle housing i0. The terminals 34 and 42 of the unit |2 are respectively connected to the rings 49. SII by the electrical conducting wires 6| and 62, respectively, as shown in Fig. 2. The brushes 56, 51 are connected with wires 63, 44.

The gauge device 35 is provided with a movable pointer for the scale I3 and five incandescent lamps 611 to 61* inclusive. 'Ihe scale 44 is calibrated to indicate under and over pressures. When the tire is at its selected operative pressure, the pointer will move to the "up position on the scale on closing the gauge switch. This is brought about by adjusting the tension on the springs 24 of the several units |2 to accord with the selected operative tire pressure. When the latter reduces, the pointer will fall short of the up" position when the switch is closed. Whereas, in case of an increase in pressure the pointer will move beyond the up position.

The lamps are in circuit with the respective pressure responsive units |2 secured to the four traction wheels A to D inclusive and the spare tire E of the motor vehicle as shown in Fig. l. It is to be understood that there is a pressure yresponsive device I-2 applied to each o! these wheels and further that only the traction wheels are equipped with the conductor ring and brush assemblies detailed in Fig. 2. For the spare tire, a direct connection is used. Hence, when the system is installed on a motor vehicle the operator thereof will be apprised by the lamps B7* to 415 inclusive whenever any of the tires vci? iig'uring in pounds of pressure.

drop below the selected operative pressure to be maintained therein. I! this is, say thirty pounds, the springs for the plungers 23 will be set to move the diaphragms inward at a pressure reduction below this figure.

'Ihe electrical system employed is arranged to indicate which tire becomes under inflated. For example, should the left front tire A lose pressure, the lamp l1l for said tire would be lighted and at the same time a sounder Il (Fig. 4) would be actuated. This occurs automatically, the pressure responsive device on said wheel functioning to close the contacts to produce this result. In like manner, the lamp S1 would be lighted and the sounder 8l would be actuated should the right front tire 'B lose pressure. 'I'his also occurs for the rear tires, the lamps I1l and l1* being connected with the left rear and the right rear tires C', D respectively. The lamp 615 is connected with the spare tire E.

The signals are operated as follows: When the plunger 23 of a pressure responsive device moves inward to engage its disc 31 with the terminal I2, the lamp in circuit with said terminal is lighted. to indicate a drop in pressure. The sounder 68 is also in this circuit. When a tire is over iniiated, the contact Il engages the terminal 42 and the lamp is lighted and the sounder is operated as before. This occurs on filling the tire with air and the over pressure can be released at the xture 9 to set the device I-2 for a normal operation. 'Ihe gauge 3B is not in the circuit at this time. The gauge is onlyfoperated when the driver of the vehicle wishes to sec whether the tires are up to pressure. This is done by operating a manual switch at each lamp. This switch mechanism, which is the same for each lamp, is detailed in Fig. 4.

As shown in Fig. 4, each lamp is mounted in a tubular casing 6! which is slidably mounted within a housing 10. The sliding supports for the casing $9 are indicated at 1I, 1I, the rear one being of insulation material. The switch mechanism heretofore referred to is locatedat the rear end of the housing 1I, comprising nxed and movable contacts 12, 1I. The former is resilient to normally press the casing I9 forwardly and break the circuit at the rear contact. The contact 12 i-s connected to the car battery 1I by a wire 15 containing a main switch 1l. The contact 13 is connected by a wire 11 to one of the gauge terminals 18. The other terminal 1S of said gauge is connected by a wire 80 with the terminal of the resistance coil 32 *through the ring 50 and its brush 56. 'I'he lamp casing carries a contact 8l which engages a contact 82 on the lamp housing 10. A wire 83 connects the contact 82 with the wire 15 and with one terminal of the sounder 6B. The latter is of the electrically operated type and has its other terminal connected by a wire 8l with the terminal 42 through the ring 49 and its brush 51. A wire connects the wire 84 into the lamp circuit.

'I'he grounds are indicated in Fig. 4. The circuitv shown in this figure is the same for each lamp and said circuits are in parallel with the circuit shown. The necessary insulation will be provided in the circuits and at the contacts where required.

The letters L and H" on the gauge 35 indicate "low and high, respectively. This has reference to the pressure condition within the tires on either side of the selected operative pressure. By this system of calibration, the operator of the vehicle is relieved of the necessity He is told by the gauge whether the tire is up to pressure or under or over that pressure. e

With the projection Il spaced inwardly from the outer wall ot the casing I, the latter provides a chamber to mount the resistance coil l2 and also has ample bottom surface i5 to clamp the diaphragm in place. The wheel illustrated is of the pressedsteel type, this providing considerable space at the hub section for pressure unit i-2 of our invention.

The signaling system herein described and shown is simple in construction and operation.

It is applicable to all motor vehicles of the char- 1. A pressure responsive device of the character described for actuating an electric signal for an iniiatable pneumatic tire, comprising a base member and an outer casing member secured thereto, said base member having a pressure receiving chamber opening towards the outer casing member and connectable with the interior of the tire to be subject to the air pressure therein, a ilexible rubber diaphragm clamped between said members and having a tubular portion ex;`

tending into the outer casing in line with said chamber and providing a continuation thereof, said outer casing having a tubular section embracing the tubular portion of the diaphragm to support the same, the tubular portion of the diaphragm having its end within the tubular section of the outer casing closed by an end wall having an integral connection with the surrounding wallof said tubular portion, a spring biased plunger slidably mounted within the outer casing and pressed inwardly against the end wall of the tubular portion of the diaphragm to force said end wall into said tubular portion towards the chamber on a pressure reduction therein by a doubling over action of the surrounding wall of the tubular portion adjacent to its connection with said end wall, and cooperating electrical contacts carried by the plunger and the outer casing, respectively, for controlling the iiow of an electric current through an electrical circuit containing an alarm device in the axial movement of the plunger within the outer casing.

2. A pressure responsive device of the character described for actuating an electric signal for an inflatable pneumatic tire, comprising a base member and an outer casing member secured thereto, said base member having a pressure receiving chamber opening towards said outer casing and connectable with the interior of the tire to be subject to the air pressure therein, a flexible rubber diaphragm having a body portion clamped between said members and provided with oppositely extending tubular portions secured to and on opposite sides of said body portion, one tubular portion extending into said chamber and the other tubular portion extending into the outer casing in line with said chamber and forming a continuation thereof, said outer casing having a tubular section embracing the tubular portion of the diaphragm extending into the outer casing, the tubular portions of the diaphragm being respectively supported by the chamber and the tubular section of the outer casing by having contact, therewith, the tubular portion of the diaphragm having its end within the tubular section of the outercasing closed by an end wall having an integral connection with the surrounding wall oi said tubular portion, a spring biased plunger slidably mounted within said outer casing and pressed inwardly against the end wall of the tubular portion of the diaphragmto force said end wall into said tubular portion towards the chamber on a pressure reduction therein by a doubling over action of the surrounding wall of the tubular portion adjacent to its connection with said end wall, and cooperating electrical contacts carried by the plunger and the outer casing, respectively, for controlling the iiow of an electric current in an electric circuit containing an alarm device in the axial movement of the plunger within the outer casing.

3. A pressure responsive device of the character described for actuating an electric signal for an inflatable pneumatic tire, comprising a base member and an outer casing member secured thereto, said base member having a pressure receiving chamber opening towards said outer casing member and connectable with the interior of the tire to be subject to the air pressure therein, a flexible rubber diaphragm clamped between said members and having a tubular portion extending into the outer casing in line with said chamber and providing a continuation thereof, said outer casing having a tubular section embracing the tubular portion of the diaphragm to Asupport the same, the tubular portion of the diaphragm having its end within the tubular section of the outer casing closed by an end wall having an integral connection with the surrounding wall of said tubular portion, a spring biased plunger slidably mounted within the outer casing and pressed inwardly against the end wall of the tubular portion of thediaphragm to force said end wall into said tubular portion towards the chamber on a pressure reduction therein by a rolling over action of the surrounding wall of the tubular portion adjacent to its connection with said end wall, a plate element carried by the plunger within the outer casing in spaced relation to the diaphragm and having a slidable, but non-rotative connection with the outer casing, and cooperating electrical contacts carried by said plate element and the outer casing, respectively, to open and close a circuit therethrough containing a signal device in the axial movement of the plunger within the casing.

4. A pressure responsive device of the character described for actuating an electric signal for an inflatable pneumatic tire, comprising a base member and an outer casing member secured thereto, said base member having a pressure receiving chamber opening towards said outer casing member and connectable with the interior of the tire to be subject to the air pressure therein, a flexible rubber diaphragm clamped between said members and having a tubular portion extending into the outer casing in line with force said end wall into said tubular portion said chamber and providing a continuation thereof, said outer casing having a tubular section embracing the tubular portion of the diaphragm to support the same, the tubular portion o! the diaphragm having its end within the tubular section of the outer casing closed by an end wall having an integral connection with the surrounding wall of the tubular portion, a spring biased plunger slidably mounted within the outer casing and pressed inwardly against the end wall of the tubular portion oi the diaphragm to towards the chamber on a pressure reduction therein by a doubling over action of the surrounding wall of the tubular portion adjacent to its connection with said end wall, a ilxed electrical contact carried by the outer casing at a point intermediate the limits of sliding movement of the plunger, and electrical contact elements carried by the plunger on opposite sides of said fixed contact and movable by the plunger into and out oi engagement therewith to close a circuit therethrough at either limit oi the sliding movement of the plunger.

5. A pressure responsive device of the character described for actuating an electric signal for an inflatable pneumatic tire, comprising a base member and an outer casing member secured thereto, said base member having a pressure receiving chamber opening towards said outer casing member and connectable with the interior of the tire to be subject to the air pressure therein, a ilexible rubber diaphragm clamped between said members and having a tubular portion extending into the outer casing in line with said chamber and providing a continuation thereof, said outer casing having a tubular section embracing the tubular portion ot the diaphragm to support the same, the tubular portion of the diaphragm having its end within the tubular section or the outeil casing closed by an end wail having an integral connection with the surrounding wall of said tubular portion, a spring biased plunger slidably mounted within the outer casing and pressed inwardly against the end wall of the tubular portion of the diaphragm to force said end wall into said tubular portion towards the chamber on a pressure reduction therein by a folding over action of the surrounding wall of the tubular portion adjacent to its connection with said end wall. a spool of insulating material carried by the plunger within the outer casing and movable therewith, an electrical resistance coil carried by said spool, and an electrical contact element slidably engaging said coil to control the ow oi an electric current therethrough in a circuit containing the coil and a signal device in the axial movement ot the plunger within the outer casing, said spool being recessed to receive the tubular section of the outer casing in the movement of the spool towards the same.

ROY ADDY. HENRY E. ADDY. 

